The inorganic solid such as silica, titanium oxide, alumina, calcium carbonate, aluminum hydroxide, carbon black, a conductive metal powder, a glass fiber, a carbon fiber, a clay mineral, a pigment (e.g. a metal oxide or a lake) is used for various purposes as a material to be blended in a synthetic resin composition, a wax composition or a liquid composition or as a functional powder (e.g. a cosmetic powder) by itself. In this case, the surface characteristics of the inorganic solid greatly affect the physical properties of various compositions or functional powders, thus often significantly suppressing the realization of desired functions.
For example, in the synthetic resin composition or the liquid composition, a surface of the inorganic solid lacks an organic affinity, thereby stripping (or removing) an interface from the medium (referring to as a matter forming a continuous phase in the composition hereinafter) or aggregating the inorganic solid, thus not only significantly deteriorating workability but also causing a fatal problem such as a significant reduction or brittleness in material strength, a deterioration in color (or hue), a conversion into a nonconductor and a separation of pigments by sedimentation. In the functional powder, there are arisen a formation of a coagulum (or aggregate), a reduction in a charging characteristic or fluidity, an exhibition of an unpleasant feeling such as a creaky feeling or the like. Because this problem becomes remarkable in particular when a total area of the interface between the medium and the inorganic solid is increased, for example when a large amount of the inorganic solid is used or when fine inorganic solids are used, a more effective utilization of the inorganic solid is limited significantly.
To lessen such the problem, various surface modifiers have been used. For example, a silane coupling agent is very expensive besides there is not satisfactory the organic affinity of the treated surface of the inorganic solid therewith. Further, the silane coupling agent works effectively due to a characteristic of the functional group thereof, when the inorganic solid is limited as silica, glass fibers, alumina or the like. While, the silane coupling agent has a serious problem that the agent does not function at all to a material lacking a reactivity, such as titanium oxide, calcium carbonate, carbon black and graphite.
An anionic, cationic or nonionic low-molecular surfactant or an aliphatic acid may be used as the other surface modifier being inexpensive for the inorganic solid in some cases but a covering (or coating) power to the surface of this inorganic solid is very weak. Thus, they have been used as the surface modifier in a significantly limited field.